Detecting a refrigerant leak in an air conditioning unit is one of the many steps to keeping your AC unit run smoothly. Although many people react by adding more refrigerant to the system, it is recommended to conduct a leak test to identify and fix before you add more refrigerant. To make life easier for people with problems detecting a leak, let’s look at the common leak detection methods available.

How to Detect A Leak in AC Refrigerant

Soap Test

Soap test, also known as bubble solution method, is the easiest way of detecting a refrigerant leak. However, it can only be performed on systems with a positive gauge pressure. This is because such a test on systems operating under vacuum may draw in moisture and result in contamination of the refrigerant or the failure of parts of the airconditioner system.

The bubble test process involves first making a soap solution from dish washer liquid and water in a container. You should then clean the area to be tested using a dry cloth. Switch on the system to either heating or cooling mode. Apply the solution to the test area and watch for bubble formation. You can use a mist spray on the hard-to-reach areas of the unit.

UV Light Detection Method

AC Refrigerant LeakSince oil is well mixed with the refrigerant, a leak of lubrication oil onto the atmosphere is a common phenomenon during the refrigerant leak. The oil usually has an ultraviolet component in it that is easily detectable using UV light, commonly referred to as black light. Due to the inability of human eyes to see ultraviolet light, the working principle of this test is that the UV light will be reflected when exposed to UV surfaces hence becoming visible to our eyes. The method includes shading the test area of the air conditioning unit and then directing the UV light onto it. Look for a fluorescent mark to identify the leak.

Electronic Detectors

The basic types of electronic detectors are the corona-suppression and heated diode. The corona-suppression detector is a device operated by measuring the variations in conductivity of gases that pass between two electrodes. The detector creates a baseline current as high voltage sparks jump from one point to another. A drop of current between these two points will indicate the presence of an insulating gas. On the other hand, the heated diode technology has a ceramic element which heats the refrigerant and breaks down molecules. The positively charged ions of chlorine and fluorine become attracted to the negatively charged electrode, and the flow of these ions create a current. As the level of these refrigerant ions increases, they reach a point that causes an audio-visual alarm on the detector. This method is more accurate than the corona-suppression.

Halide Detectors

This method uses a halide torch and is based on the fact that the flame of this torch will turn green when exposed to chlorine and fluorine atoms present in the refrigerant. However, the method is not always reliable since not all refrigerants contain the chlorine atoms. It also requires certain precautions to be adhered to while using it. If you want more tips, check out our these Four HVAC Repair Facts.


Contact Us